Achilles tendon rupture is the most common injury involving a tear in a tendon. it commonly occurs as a sports injury during explosive acceleration, for example, while pushing off or jumping up.
Treatment of Achilles tendon rupture is typically divided between operative and non-operative management, each of which involve the gradual stretching of the tendon after the rupture has healed.
Operative management involves a surgical operation where the ruptured tendon is sutured back together at the point of rupture, and the leg is then placed into a cast. When the leg is placed in the cast, the foot is pointed downward (in an equinus position). As the healing progresses, the equinus position is then gradually decreased (requiring removal of the original cast, and recasting with the newly decreased equinus position).
Non-operative management typically involves wearing a cast or walking boot, which allows the ends of torn tendon to reattach themselves on their own. In the non-operative option, the foot is pointed downwards, with the help of heel wedges or insoles, which are placed in the walker boot. The height of the heel wedges or insoles is then incrementally decreased as the process of healing progresses. One disadvantage of using the heel wedges is that reducing the height of the wedges/insole can be too drastic for the injured tendon.
Both the operative and the non-operative methods involve a long rehabilitation process, lasting at least 6 months. Additionally, in each situation, removal of the cast or walking hoot is necessary in order to adjust the equinus position of the foot, and/or to remove and replace heel wedges or insoles having a different height.
Non-operative treatment might seem like a more comfortable way to go about Achilles repair, but it does take longer and leaves the patient with a greater risk of re-injury. Immobilization using a plaster cast can take as long as 12 months for the tendon to return to full strength, whereas surgery may only require anywhere from 6 to 9 months. In the past, patients who underwent surgery would wear a cast for approximately 4 to 8 weeks after surgery and were only allowed to gently move the ankle once out of the cast. Recent studies have shown that patients have quicker and more successful recoveries when they are allowed to move and lightly stretch their ankle immediately after surgery. To keep their ankle safe these patients use a removable boot while walking and doing daily activities.
In either the operative or the non-operative situation, existing methods for stretching the Achilles tendon can be time-consuming and inconvenient to implement. Additionally, existing methods for stretching the Achilles tendon can cause drastic changes in stretching the length of the Achilles tendon, such that the risk of re-rupture of the tendon is increased.